Remote control system



July 11, 1933. 'J. 0. CARR REMOTE CONTROL SYSTEM Filed Feb. 8, 1932 2 Sheets-Sheet 1 6 5 4 a 0L S INVENTGR. 85 JOHN 0. 0422 BY j; 73

as as A TTORNEX July 11, 1933. J. o. CARR 1,917,294

REMOTE CONTROL SYSTEM Filed Feb. 8, 1932 2 Sheets-Sheet 2 CONTROL 5 1 2 3 4 5 8 7 8 9 l0 4 O o O O 0 INVENTOR.

5 0 0 0 JOHN 0. mp2

ATTORNEY.

CLEAROUT 00000000 0 Patented July 11, 1933 UNITED 'STA'I ES PATENT OFFICE JOHN O. CARR, OF CHICAGO, ILLINOIS, ASSIGNOR TO TELETYPE CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF DELAWARE REJHOTE CONTROL SYSTEM Application filed. February 8, 1932. Serial Ho. 591,534.

This invention relates to methods and systems for remote control and more particularly to methods and systems for remote control applied to radio communication systems.

Systems in which remote units are selectively controlled to perform various opera-- tions practically eliminate the use of attendants at points Where remote-control apparatus are located, by providing control of these i apparatus at a centralized point where a single operator may have under his direct control all of these remotely disposed apparatus. This not only reduces costs, but provides systems of great flexibility because of 1 this common control. Such systems are moreover essential in cases Where the controlled apparatus is located at a position not easily accessible by an operator or which, for any special reasons, it is desired to be 2 remotely controlled.

Remote control systems, however, have encountered difliculties due to interference from extraneous source-s on the signalling system which have, in some instances, caused incorrect operation of the remote unit. These interferences may be due to stray currents from other signalling systems or to deliberate intrusion on the system by unauthorized individuals. In wire circuits, this may be done by tapping signalling wires. In radio transmission to which the system of this invention is particularly adapted, it may be done by transmitting, inimical control operations on the same wave length.

The objects of the present invention are a remote-control system and its method of operation which are extremely simple, possesses considerable flexibility and are effective against intrusion.

This invention provides means for sendingtelegraphic signals in rapid succession by radiant energy, and provides iurther means for receiving, recording, interpreting and again recording those signals which represent transmitted intelligence. It provides first-record means for all received signals but provides second-record means for only a limited number of the many possible codes of signals. Modification means is also provided for the interpreting devices whereby the number of predetermined codes to be transmitted to the second-record devices may be reduced, thereby decreasing the likelihood that chance signals or deliberate-interference signals will have any influence upon the second-record means and thereby upon the work to be done by the transmitted intelligence.

A clear understanding of the invention may be had from the following description, taken in conjunction with the accompanying draw ings, wherein, 3

Fig. 1 is a circuit diagram of the-transmitter in a radio system embodying this invention.

Fig. 2 is a circuit diagram of a receiver illustrating one adapation of this invention. F Fig. 3 is a table of codes for. the system of Fig. 4 is a circuit diagram of a modification of the selecting circuits of Fig. 2.

' Fig. 5 is a table of codes for the system of Fig.4.

An operating station or central control station 10 is connected to a remote station 11 by means of a radio channel. At station 10, a keyboard 12 having keys 1 to 8 and C O is arranged according to principles of tit automatic telegraphy to control selectively the closi g of a combination of contacts 13 in.

various permutations according to the signal to be transmitted. In addition to the selec 'tively operated contacts 13, the keyboard is the operating contacts. for a code are sequentially associated with the signalling system in a manner well known in the art and a group code of unit signals 1s transmitted.

Although as shown the keys carry designue I tions of numerals and letters, it will be un- 'derstoodsthat for the purpose of the present invention, designations of the desired remote operations will preferably appear on the key levers.

An amplifier and radiotransmitter 17 with antenna 18 convert batterysignals impressed upon wire 16 into radiant energy signals upon the antenna 18. I

At the remote station 11, a receiving antenna 21 is connected to an amplifier-detector 22, the output circuit of which controls a relay 23 which in turn by its contacts con- 'trols the current through a distributor 24.

The signal codes sent to the wire 16 by the keys of keyboard 12 may be as indicated in Fig. 3. In Fig. 3, the seven time-periods of a code are shown by seven parallel columns, in which the columns S indicates the starting signal, columns-1, 2, 3, 4, 5 indicate the signals for the selective code, and column 6 indicates the stop signal, constituting a resumption of the idle condition of the line circuit. In Fig. 3, the idle condition is the continuous connection of battery 15 to the wire 16 at station 10, the transmission of no radiant energy from antenna 18 to antenna 21 and the continuous engagement of the armature of relay 23 with itsback contact S at station 11. In Fig. 3 each horizontal line shows at the left the label of a key in the keyboard 12 of Fig. 1, and at the right of the label in the row are shown in the seven columns the closed or open condition of the contacts 13-14 in each of the seven timeperiods represented individually by the seven columns. Thus'it is shown that upon the operation of key 2 in keyboard 12, a code will be sent comprising one time-period of no-current on wire 16, followed by two timeperiods of current on wire 16, followed by three time-periods of no-current on wire 16, followed by the normal idle condition of current on wire 16.

The distributor 24 comprises two segmented rings 27 and 28, over which a brush 29 rofitates to distribute the received impulses in a manner to be described. The brush 29 is mounted on and rotatable with a shaft connected through a friction clutch (not shown) .to the rotating member of a continuously operating motor (not shown). The brush 29 is normally in operative engagement with a stop-armature 30. The armature 30 is pivoted to the framework (not shown) and is normally held in engagement with the brush 29 by a spring, one end of which is secured to the armature 30 of an electromagnet 31 and the otherto the framework.

The operation of the armature 30 is controlled by the electromagnet 31, which is connected from ground over the conductor 32 to the stop segment 33 on the distributor 24. The front contact M of the relay 23 is connected to segment 34 of the distributor '24. With the distributor in the position shown, the circuit for the starting 'magnet 31 may be completed from ground through battery, over front contact M of relay 23, segment 34, brush 29, segment 33, conductor 32, electromagnet 31 and return through ground. The electromagnet 31 being normally non-energized permits its armature 30 to engage the brush 29 and the distributor brush arm is held from rotation, thus slipping the friction clutch of the continuously rotating motor.

As illustrated, four of the other segments 36, 87 ,,38, 39 of the ring 28 are electrically connected to individual selector relays 41, 42, 43 and 44, respectively, and segment is connected to and through the armatures and contacts of the four selector relays. The remaining segment 45' of the ring 28 is connected to an unlocking relay 46 and its companion segment is connected to battery.

Individual to the selector relays are looking armature-contacts 48 and operating armatures 50 to 60, inclusive.

The nine contact points of the operating armatures 56 to 60 of the selector-relay 44 are connected to eight operating relays or secondrecord relays 61 to 68 and a clearin relay or enabling relay 69. Each of the re ays 61 to 68 has a pair of locking contacts 70 which close a locking circuit from earth through the relay winding, then contacts 70, wire 71, lockout relay or disabling relay 72, wire 73 and contacts 73 of clearing relay 69 to battery.

Each of the relays 61 to 68 has also a pair of operating contacts 74 which close a circuit from battery through contacts 75 of clearing relay 69, then through contacts 74 severally to the work-units 81 to 88 severally, and to earth. The divide relay 72 opens the operating circuits of all relays 61 to 68 but not of the clearing relay 69.

In operation, briefly, the controlling station 10 of Fig. 1 sends a start-stop code which at the remote station 11 of Fig. 2 operates a relay-selector which selects and operates one of the second-record relays 61 to 68. The selected relay locks, and thereby operates the divide relay 72 which disables all relays eligible to the selector except the clearing relay 69. The second-record relay also energizes one of the work-units 81 to 88. As long as the system is left in this condition, thirty-two permutation signals may be sentpupon the fivepermutation time-periods of columns 1 to 5 in Fig. 3, but no signals upon the antenna 21 will have eflect except the clearing signal which will operate the relay 69 and will release all relays 61 to 68 after which a second code may be sent to select the same or another second-record relay. 3

It is obvious that the system is open to interference by any of a plurality of code combinations of signals upon antenna 21 when the divide relay 72 is not operated, but is open to but one code, the clearing code, when the divide relay 72 is operated.

To utilize further this feature of safety in the operation of the system, a non-operating second-record unit is provided as shown by the relay 67 wherein the locking current through the relay 67 operates thedivide-relay 72 but wherein the omission of the earth connection upon the unit 87 renders the unit 87 ineffective. During intervals when it is not desired to operate any work-unit, the divide relay 72 may be held charged by selecting the second-record relay 67, thus operating the relay 72 to guard other second-record relays from operation until the clearing relay 69 shall have been operated. The sending of the next operating code then is prefaced by the clearing code, which is a full code including the starting signal, as shown in Fig. 3, the system of this invention being thus less open to willful interference than any system which might be conditioned by a single signal impulse even though that single impulse must have a proper time relation with a synchronous distributor.

In detail, the operation of effecting the energization of the work-unit 82, for eXample. is as follows:

The operator at the station 10 depresses key 2 of the keyboard 12. This starts the sender 1314 and a start-stop telegraphic code is sent over the wire 16 according to the code 2 of Fig. 3, as follows, open-closedclosed-0pen-open-open, after which the normally closed condition or stop-condition will be resumed and maintained until a subsequent code is sent.

The normal condition of the antennae 18 and 21 being no-current, the code sentwill result in a unit-length start signal of radiant energy, followed by a two unit time-period of no-current signal, followed by a threeunit-length signal of radiant energy.

The start signal operates relay 23 to close its contact M, which operates magnet 31 and the brush 29 starts. During the twounit interval of no-signal, the relay 23 holds its Contact S closed and the brush 29'charges the two selectof relays 41 and 42, which lock through contact of relay 46. During the three-unit signal the relay 23 closes its contact M. Brush 29 passes segments 38 and 39 without charging the relays43 and 44. This point in the progress of the brush 29 marks the completion of selection, since the operated condition of selector relays 41 and 42 jointly with the non-operated condition of selector relays 43 and 44 effects the preparation of the selective circuitof relay 62. in the selector, subject to closure at the third contact of relay 72 and at contact 40 of the distributor and at the contact M of the line relay 23. The relay 72 at this time will be found uncharged and with its contacts closed.

The selection thus prepared is rendered effective by an executive signal from the control station through the relay 23. The executive signal is indicated in column 5 of Fig. 3 and it is timed at station 11 by the engagement' of brush 29 with the segment 40, completingt-he selector circuit, which charges the second-recordrelay 62 over the circuit from relay 23, contact M, brush 29, segn'lent 40, armature 50- and front contact, armature 51 and front contact, armature 53 and back contact, third contact of relay 72, wire 89, armature 57 and back contact, wire 90, relay 62 and earth. Relay 62 Operates and locks up over the circuit from contact 73 of relay 69, wire 73, relay 72, wire'71, contact v of relay 62, winding of relay 62 and earth,

thereby operating the relay. 72 and locking both relays 62 and "72. Relay 72 disables all relays 61 and 63 to 68. Relay 62 also closes its contact 74 and energizes the workunit 82. At segment 45, the brush 29 closes a circuit to energize the relay 46 and thus to unlock the used relays of the selector-relays 41:0 44. p

The next effective code will be the clearing code which is identical with code 2 except that all relays 41, 42, 43, 44 are charged and relay 69 is operated momentarily over wire 91..

Dou-ble sclecto'r In Fig. 4 is shown a modification of Fig. 2 in which the codes are longer and are more difficult of simulation by interference. The

111, 112, 113, 114 with their locking points 48, and with their operating armatures'120 to 130. The second-record relays 61 to 68 have separate windings for their locking circuits. I

For operation with the remote station of.

Fig. 4, the controlling station 10 of Fig. 1 will require additionalcontacts 13- The code for operating the system of Fig. 4 is shown in Fig. 5. It is a start-stop code comprising nine pern'lutation signals combined with a start signal, shown in column S and a stop signal shown in column 10.

In the code as shown, the units 5, 6, 7 and 8 are duplicates of the units 1, 2, 3 and 4, re-

spectively, thus making the relay armatures 120 to 130, duplicates of armatures 50 to 60 respectively, but this is not a limitation of this invention. Any permutation of signalsmay be used and the relay armatures and contacts connected to correspond to the code.

A feature of the invention is divlding the selector relays into two groups, arranging the contacts of each group in the form of a circuit fan, connecting the operating relays between the two fans and confining the contacts of the divide relay to the connectors of one of the fans, since thereby the total number of fan and divide contacts may be made a minimum.

In operation, the system of Fig. 4 is similar to the system of Fig. 2 except.for the longer code group and for the tracing of the operating paths through the circuit fans. To charge the second-record relay 62, code-2 of Fig. 5 is sent and received, thus charging and locking the selector relays 41, 42, 111, 112. The relay 62 then is charged over the circuit (Fig. 4) from relay 23 front contact, brush 29, segment 40, armature 50 and front contact, armature 51 and front contact, armature 53 and back contact, right-inner contact of relay 72, wire 89, armature 57 and back contact, wire 90, right winding of relay 62, back contact and armature 127, back contact and armature 123, front contact and armature 121, front contact and armature 120 to earth. Relay 62 operates and locks by its left hand winding and armature over a circuit from battery through winding of relay 72, wire 73, left contacts 73 of clearing relay 69, left contacts (70) of charged relay 62, left winding of relay 62, and to earth, thus operating the relay 72 and locking both relays, 72 and 62. Relay 72 disables all second-record relays 61 and 63 to 68. Relay 62 also closes its right contacts 72 and energizes its work unit, not shown in Fig. 4. At segment 45 the brush 29 closes an obvious circuit to energize relay 46 to unlock the used selector relays. 1

Variations and developments may be made without-departing from the spirit of the invention. The radiant transmission may be a continuous signal with brief breaks. The selector may be of any type. A relay selector has been shown because it is a simple form of selector where the total number of selections is small. The synchronism may be of any type such as the start-stop method of synchronism or the continuous method of synchronism.

Although the invention has been described in connection with a specific form thereof, it will be understood that it has further application and it is not intended to be limited bythe specific embodiment shown for illustration.

The invention claimed is:

1. The method of controlling remote apparatus which comprises sending a start-stop conditioning code for conditioning the remote apparatus to respond to codes other than a start-stop conditioning code, sending a startstop selecting code for initiating a desired work at the remote apparatus, sending a start-stop clearing code for terminating the initlated work, and sending a start-stop lockout code for disabling the remote apparatus from responding -to any code other than a start-stop conditioning code.

2. The method of controlling remote apparatus which comprises sending a code for conditioning the remote apparatus to respond to other codes, sending a code for initiating a desired work at the remote apparatus,sending a code for terminating the initiated work, and sending a code for disabling the remote apparatus from responding to any code other than a code for conditioning, each and every of said codes being a group code of uniform length and being composed of unit signals and comprising a selecting signal followed by an executive signal, the selecting signals being variant in all codes and the executive signal being uniform in a plurality of codes.

3. The method of controlling remote apparatus which comprises sending a code for conditioning the remote apparatus to respond to other codes, sendlng a code for initiating a desired work at the remote apparatus, sending a code for terminating the initiated work, and sending a codefor disabling the remote apparatus from responding to anycode other than a code for conditioning, each and every of said codes being a group code and all of said codes being of uniform length. 4. In a remote-control system, operating relays, a lock-out relay for disabling said operating relays, a clearing relay for enabling said operating relays, and a selector responsive to line signals for selectively rendering said several relays individually responsive each to aacode combination of line signals. I

5. In a remote-control system, a control station, a transmitter at said station adapted to send code signals, each such code signal comprising a selective component followed by an executive component, and a remote apparatus comprising an operating relay, a lockout relay for disabling said operating relay, a clearing relay for enabling said operating relay, and a selector responsive to the selective component of a code signal for selectively rendering said several relays responsive to the executive component of the code signal.

6. In a remote-control system, a control station, a remote station, a selector at said remote station and responsive to signals from said control station, a plurality of relays for selection in response to remote control codes of signals, selector circuits individual to said relays for selecting them, said' circuits each normally open at a line-signal-control point, lock-out. means responsive to code signals from said control station for opening and closing all of said selector circuits at a localcontrol point, means in said selector for preparingone of said selector circuits at all points other than at the local-control point utive means for closing said selector circuits at the line-signal control point in response to a specific signal, whereby the successive operation of saidlock-out means, said selector and said executive means may close completely a desired selector circuit and effect the ener-.

' said operating relay, said second relay oper- 15,

ating also to terminate the operation of said operating relay in response to remote-control signals.

8. In a re1note-control system, an operating relay, a local selecting circuit for said relay, means for enabling and disabling said selecting circuit, a selector responsive to remote-control signals for controlling said means and for closing said selecting circuit to initiate the operation of said operating relay, and a local locking circuit for locking said operating relay, and for controlling said means.

cuits to initiate the operation of one of saidv operating relays, and a local locking circuit for said operating relay, said disabling relay operated by said local locking circuit to open said selecting circuits.

10. In a remote-control system, a control station, a remote station, a selector at said remote station and responsive to signals from, said control station, a plurality of operating relays for operation by remote control, selector circuits individual to said operating relays and through contacts in said selector, a lockout relay for opening said circuits, a further operating relay for operation by remote-control, and a further selector circuit individual to said further operating relay and through contacts in said selector and operable by said selector while said lock-out relay is in operated condition.

11. In a remote-control system, a control station, a remote station, a selector at said remote station and responsive to signals from said control station, a plurality of relays for operation by remote control, selector circuits individual to said relays and through contacts in said selector, and a disabling relay for opening said selector circuits, said disabling relay operated by an operating one of said relays.

12. In a remote-control system, a relay selector comprising a plurality of relays divided into two groups, the contacts of the relays of each group connected in fan formation, electromagnetic units to be selected connected between the terminal conductors ofthe two fans, and a disabling relay having its,

points connected in the conductors of one only of the fans.

13. In a remote-control system, a relay selector comprising a plurality of relays divided into two groups, the contacts of the relays of each group connected in fan formation, and electromagnetic units to be selected connected between the terminal-conductors of the two fans.

14, In a remote-control system, a plurality of relays, selector circuits for energizing said relays, a lock-out device for disabling said selector circuits, a clearing device for re-enabling said selector circuits, and a set of selector relays operable repeatedly by variant sig nal codes to operate said clearing device and to select one of said selector circuits;

15. In a remote-control system, a plurality of relays, selector circuits individual to said relays, a selector responsive to codes of signals for selecting one of said circuits, a lock-out device for disabling said selector circuits and operable by any of said relays whereby but one relay may be operated at one time, and

a clearing device operable by said selector in response to a code of signals for re-enabling said selector circuits, all of said codes being of uniform length.

16. In a remote-control system, a selector operable by remote control, a plurality of relays, selector circuits for said relays, a local device for disabling all of said selector circuits and operable by any one of said relays, whereby but one of said relays may be operated at one time, and a device operable by said selector for re-en'abling said selector circuits. r

17. In a remote-control system, a plurality of devices, selecting apparatus responsive to received code combinations of impulse conditions for variably operating said devices, said devices being normally non-efiective in response to the selective operation of said selectors operating in accordance with received combinations of impulses, and a device common to all of said devices operated by said selectors in accordance with a predetermined code combination of impulses for rendering said other devices I responsive thereafter in accordance with the operation of said selectors by said received code combinations of impulse conditions.

18. In a remote-control system, a plurality of devices, selecting apparatus responsive to received code combinations of impulse conditions for selecting one of said devices for operation, said devices being normally non-responsive to the operation of said selecting apparatus, a common means operated by said selecting apparatus in accordance w1th a predetermined code combination of impulse conditions for rendering said devices operative, any one of said devices upon operation remaining operative independent of said common means, and further means controlled by 5 said devices for rendering said devices nonresponsive to further code combinations of impulse conditions whereby only one of said devices is operated at a time.

p 19. In a remote-control system, a plurality l of relays, selecting apparatus responsive to received code combinations of impulse conditions for selecting one of said relays for operation, said relays however being normally non-responsive to the operation of said selec l tors, a further relay operated by said selectors in accordance with a predetermined code combination of impulse conditions for rendering said first relays operative, and means controlled by said selectedrelay for rendering any similar relay non-responsive to its individual code combination of impulse conditions whereby only one of said relays is operated at a time.

20. In a remote control system, a plurality of devices, selecting apparatus responsive to received code combinations of impulse condi- In testimony whereof I aflix my signature.

JOHN O. CARR. 

